Screw-driver



UNITED STATES PATENT rrrcn SCREW- DRIVER.

SPECIFICATION forming part of Letters Patent No. 393,421, dated November27, 1888.

Application filed April 28, 1888.

.To (tZZ whom, it may concern:

Be it known that I, FELIX CHANTRELL, a citizen of the United States,residing at Heading, in the county of Berks and State of Pennsylvania,have invented certain new and useful Improvements in Screw-Drivers; andI do declare the following to be a full, clear, and exact description ofthe invention, such as will enable others skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, and to the letters and figures of referencemarked thereon, which form a part of this specification.

This invention relates particularly to hand tools-such as screw-driversin which it is desired to rotate the handle with or without the shaft.

The object is to accomplish this in a more satisfactory and efficientmanner, and at the same time more economically than has heretofore beendone. The means now in use to secure the desired results in tools of thekind referred to involve the use of a serrated or toothed surfacearranged at right angles to the axial line of the shaft, the separateparts being revolved together when the serrations or teeth on onesurface are brought into engagement with corresponding serrations orteeth, a pivoted dog, or equivalent, device on the other. Thisconstruction becomes more or less complicated and expensive, and whenthe teeth or equivalents are sufiiciently strong and present enoughsurface to prevent excessive wear a considerable longitudinal movementis required to throw the parts into or out of engagement, and there isalso an objectionable amount of circular lost motion before the teeth onone surface coincide with the correspond ing recesses on the other.

In my device I discard the serrations or teeth above described andsecure the requisite engagement between the revolving parts on the outersurface of a tapered shank end, a preferred construction on thisprinciple being illustrated in Figures 1 and 2 of the drawings, Fig. 1being an elevation, partly in section, of a complete screw-driver, thehandle and shaft being represented out of engagement, Fig. 2 giving anisometrical view of the handlebushing detached. Fig. 4 is across-section of the handle-bushing.

Serial X0. 272,124. (NouiodeL) A represents a wooden handle, theexternal appearance of which does not differ from those ordinarily usedfor screw-drivers and similar tools. It is, however, bored centrallythrough its entire length to two different diameters, the larger part ofthe hole Leing in the heavy pant of the handle, while the smaller boreextends through its reduced part, leaving an interior shoulder oroffset, A, where the two sizes conneet.

The shaft B is a round piece of rolled steel tapered and shaped at oneend to suit ascrewslot.. Its diameter is such as to loosely fit thesmall bore of the handle, into which the plain shank end of the shaft isinserted until itpro jects beyond the heavy end of the handle. Thecap-piece D, which is represented in the form of a frustum of a pyramid,the base or a parallel section of which at any point of its height is amany-sided polygon without re entering angles, and which is also formedwith a hole suited to the size of the shaft, is then forced on orotherwise securely fastened to the shank of the shaft, which issubsequently allowed to drop until the base of the rap rests upon theoffset A in the handle.

The handle-bushing O (as also the cap-piece D above described) may becast of malleable iron or other metal, the outside longitudinalcorrugations, O, or their equivalent, as well as the interior shape,with flat faces C corresponding with the outside surface of the cap D,being formed complete in the foundry, ex-

cept that a properly-shaped tool may be driven into it to remove sandand burrs and so insure its fit on the cap. The bushing is sufficientlylong to give room for a spiral spring, E, between the end face of thecap (when the latter is inclosed by the bushing) and the shoulder (J inthe top part of the latter, which forms a seat for the spring.

The above-described bushing, which is of such an outside diameter aswill tightly fit the large bore of the handle, and is also slightlytapered or rounded at the bottom to permit of its being readily entered,with the spring E inolosed, is pressed into the handle, the surplus woodbeing compressed and forced into the grooves C until the cap D isinelosed by the bushing as far as possible without engag ing with itwhen the base of the cap is pressed against the offset A by the spring.The plug 1 F is then glued or otherwise fastened in the handle above thebushing, which latter is thus effectually prevented from pushing out orturning in it. This method of securing a sleeve or equivalent in theheart of the handle has been previously described and claimed in mypending application, Serial No. 267,66l, and the means herein set forthfor engaging the handle and the shaft is an improvement on my previousapplication, Serial No. 266,331.

The method of operating a tool constructed as above described isobvious. XVhen applied to a screw-driver, as shown, the point beingplaced in the screw-slot, a moderate end pressure on the handlecompresses the spring and permits the shank-cap to seat itself in thesleeve. WVhen the handle is then rotated, the shaft and screw rotatewith it, the tlat sides and corners of the cap and sleeve. respectively,compelling them to turn together. On removing the longitudinal pressurethe spring moves the handle just sufiicieutly to allow it to be returnedwithout engaging the shaft, which remains stationary until the handle isagain rotated in the same direction. The hand which grasps it need notbe shifted.

The advantages of this general method of construction consist, aspreviously noted, not only in increased economy of manufacture, but alsoin more satisfactory working, consequent on the large surface of theshank which is thrown into engagement with the handle by a slightmovement as compared with the use of the usual end serrations or teeth.

I do not wish to limit myself to the construction shown, as it isobvious that various modifications may be readily devised. Fig. 3represents one equivalent form in which the cap-piece is dispensed withand the end of the shaft itself shaped to suit the sleeve, the lat terbeing of smaller diameter than that shown in Fig. 1. The method hereindicated of preventing the withdrawal of the shaft by means of aprojecting stem, G, extending through the bushing and having a head, G,formed on the end of it, is similar to that described in my pendingapplication, Serial No. 266,331.

What I desire to secure are the following claims:

1. In a screw-d river or similar tool, a drivershaft having a taperedshank end of regular polygonal crosssection, in combination with arotatable handle provided with a fixed bushing having its interiorshaped to correspond with said shank end, and a spring. all adapted tooperate substantially as set forth.

2. The driver-shaft having a cap'piece of regular po ygonalcross-section secured to its shank end, in combination with a rotatablehandle provided with a correspondinglyformed bushing adapted to engagesaid cappiece, and a spring, all adapted to operate substantially as setforth.

In testimony whereof I affix my signature in presence of two witnesses.

FELIX CHANTRELL.

Witnesses:

GARRETT B. STEVENS, F. PIERCE HUMMEL.

